POS1520 RELIABILITY STUDY OF THE SLE-DAS, SLEDAI-2K AND PGA INSTRUMENTS FOR MEASURING SLE DISEASE ACTIVITY
Authors: B. Mendes, C. Mazeda, D. Jesus, H. Assunção, A. Barcelos, L. Brites, D. Carvalho, C. Costa, E. Costa, A. D. Vieira Bento Silva, M. Santos Faria, G. Eugénio, M. Luis, A. Maduro, M. Lucas Rocha, B. Samões, F. Cunha Santos, A. Saraiva, S. P. Silva, C. Vaz, J. P. Vilas, J. A. P. Da Silva, L. Inês
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> The Systemic Lupus Erythematosus Disease Activity Score (SLE-DAS) has been recently developed and validated, providing improved accuracy and sensitivity for changes in SLE disease activity in comparison to SLE Disease Activity Index 2000 (SLEDAI-2K) <sup>[1]</sup>. New recommendations to standardize the Physician Global Assessment (PGA) scoring may improve its reliability <sup>[2]</sup>. <h3>Objectives</h3> To assess the intra- and interrater reliability of SLE-DAS, SLEDAI-2K and PGA for measuring SLE disease activity. <h3>Methods</h3> A set of 24 clinical vignettes were abstracted, each from a real clinical visit of patients followed at an academic lupus clinic. These vignettes were selected to include a wide spectrum of SLE manifestations, organ-system involvements, and global severity of disease activity. Abstracted data were presented in a standardized format, including demographic, past medical history, current clinical picture and treatment, laboratory, and other workup assessments. A group of 19 raters were recruited as a random multicenter sample of Rheumatologists. All raters completed a preliminary training session on scoring rules for SLE-DAS, SLEDAI-2K and PGA. Each rater scored each clinical vignette with SLE-DAS, SLEDAI-2K, and PGA through an online survey. The scoring was repeated in a second round 7-14 days after the first one. The clinical vignettes were randomly ordered for each round. Inter and intra-rater reliability of each instrument was estimated using the intraclass correlation coefficient (ICC) with 95% confidence intervals (95%CI), based on single-measurement, absolute agreement, with a two-way random effect or two-way mixed-effects model, respectively. <h3>Results</h3> The 19 raters included 8 rheumatologists and 11 rheumatology trainees from 11 hospitals, with a mean of 12.1±7.1 and 3.6±0.5 years of rheumatology practice, respectively, and 78.9% of the participants assess ≤5 SLE patients per week in their regular clinical practice. The 24 clinical vignettes included 83.3% female patients, with a mean of 36.5±17.9 years of age. Active SLE organ involvement included: skin rashes (20.8%); arthritis (12.5%); nephritis (12.5%); thrombocytopenia (12.5%); cardiac/pulmonary involvement (12.5%); mucocutaneous vasculitis (8.3%); serositis (8.3%); neuropsychiatric lupus (8.3%). Systemic vasculitis, myositis, alopecia, hemolytic anemia, and leukopenia were each present in 4.2% of the vignettes. Hypocomplementemia and/or high anti-dsDNA were present in 75.0%. Twenty-one percent of the cases were in remission. All raters completed the survey, totaling 912 case assessments. Scores attributed by the raters ranged from 0.37 to 49.53 in SLE-DAS, 0 to 24 in SLEDAI-2K, and 0.0 to 3.0 in PGA. The interrater reliability was good for SLE-DAS and SLEDAI-2K, and moderate for PGA. The intra-rater reliability was excellent for SLE-DAS, and good for SLEDAI-2K and PGA (Table 1). <h3>Conclusion</h3> SLE-DAS presents high intra- and interrater reliability for measuring SLE disease activity. The high reliability of SLE-DAS is an important quality both in clinical practice and research, allowing consistent scoring among different clinicians including those who are not SLE experts. <h3>References</h3> [1] Jesus D, Matos A, Henriques C, et al. Derivation and validation of the SLE Disease Activity Score (SLE-DAS): a new SLE continuous measure with high sensitivity for changes in disease activity. <i>Ann Rheum Dis</i> 2019;78:365-71. [2] Piga M, Chessa E, Morand EF, et al. Physician Global Assessment International Standardisation Consensus in Systemic Lupus Erythematosus: the PISCOS study. Lancet Rheumatol 2022;4:e441-e449. <h3>Acknowledgements</h3> Beatriz Mendes and Carolina Mazeda contributed equally and share first authorship. <h3>Disclosure of Interests</h3> None Declared.